Tiling Question

Bathroom floor tiles - grout between tiles cracked and chunks sinking, tiles lifting

I had a new bathroom completed just over a year ago. It was a local bathroom shop that did the complete bathroom refit and it was very expensive. The grout between the porcelain floor tiles started to crack and then chunks of grout sunk down leaving gaping holes. 2 of the large tiles are now rocking and now the grout all over floor seems to be doing the same. I contacted the shop over 4 weeks ago and they still haven't got anybody out to look at it, let alone sort it. I'm scared that they will try and fob be off or try and charge me to sort.

Can anybody advise why this has happened and how I go about arguing my case incase they try and fob me off. I know nothing about tiling, but I would expect that bathroom floor tiles should last way longer than this!!! :-/


Thank you so much for the replies. I do remember the guy put some kind of boarding down before tiling, but not sure what grout or adhesive was used. The grout seemed very chalky and started cracking within the first week and he came back and grouted over again. Fingers crossed they'll come and sort soon.


They have finally been out to try and sort. All though it wasn't good news. They took up all the old tiles and replaced the 9mm plywood with 12mm plywood. They then told me that my floor was not suitable for tiles!! They have told me to look for vinyl flooring as an alternative and they will pay for it. I'm not happy. I asked whether I would get a refund for the difference in cost - as I paid a lot for the porcelain flooring tiles - they didn't answer that question - they just stated we will pay for the new flooring. I have spent my day going around flooring shops looking for an alternative, but it's so depressing because I want the tiles that I chose originally. I have found something that 'will do', it's vinyl flooring by Tarkett - does anybody know if this is a good brand of flooring??

14 Answers

Best Answer

Hi, sounds like the tiles are fitted on timber floor. Flexible adhesive should have been used and possibly a board fitted to floor over original boards.
Difficult to be exact but sounds like the problem. The tiles will have to come up and be re-laid.

Answered 16th Jul 2014


Member since 29 May 2014

If it was fitted in an upstairs bathroom they should of glued and screwed hardiebacker board to act as your sub floor, 6mm would have been fine if your floor was pretty level.
They then should have used a rapid flex cement based adhesive, BAL or MAPEI , this is usually walkable within 3 to 4 hours, finished of with a flex adhesive. If this had all been done correctly you would have had no movement at all.

Answered 13th May 2016

Prestige Tiling & Bathrooms

Member since 13 Nov 2015

This is due to bad workmanship,but being that it was done over a year ago you might have a problem with the shops guarantee.The only way to solve this is to get a tiler in to have a look to see what the fault is ,it could be one of many such as bad substrate,bad fixing or wrong adhesive,but it should last longer than a year,then approach them with the verdict,I cant see them charging you if they want to keep their reputation.
Hi, I think they are trying to wriggle out of the job, its total rubbish that the tiles are not suitable,if thats the case then why did they not know this in the first place,and as for removing the ply and replacing it with ply ,when they should of replaced it with cement board,9mm ply is not good enough,tell them you want tiles and if they dont play ball go dowm the legal route ,also I would suggest that you get another tiler to have a look It seems to me these people have not got a clue.

Answered 16th Jul 2014

A. G. Fright Tiling Specialist

Member since 28 Feb 2011

In my lenghty experience, i can safely say, that when any tiled floor shows signs of lifting, as this, there's a fault.
Firstly, the wooden floor should have bee overplyed with 18mm. marine ply.
Not chipboard, or anything other than marine ply.
Then with the use of flexible adhesive and grout, there would never be a problem.Lastly, the ply should be screwed down. NOT NAILED.

Answered 24th Jun 2015


Member since 24 Jun 2015

No feedback

Hi :) first of all sorry to hear what you've been going through. Improving your home should be a pleasant experience. Sadly it seems you've fallen victim to bad workmanship.
The first point you brought to my attention confirmed this. The grout has been incorrectly installed. When grout is applied too wet it does not dry to its full strength and over time can crack and break apart. The way the grout sank into the grout joint confirms it was too wet when installed, however im sad to say this isn't the only issue you have. The tiles have not been correctly bonded to the substrate. This can be caused for 2 reasons. 1 .movement too great and floor was not correctly prepared. 2. Its not fixed in the correct method either using the wrong adhesive, or preperation materials.
Sadly this is where i believe you have the issue. Tiles cannot and should not be stuck directly to plywood unless covered first with a decoupling membrane. The reason for this is because plywood is a live product. It expands and contracts at a different rate too the adhesives and tiles. If it was stuck to the plywood directly then it would explain the debonding of tiles. The only remedy is to start over. The ply should have been a minimum of 12mm in the first place and screwed down every 150mm. If the process of preparing the floor is done correctly then you can have whatever you wish. Seems to me as if he just wants you out of his hair by offering to do vynl flooring. As a customer you should get what you want. I hope this comes to a satisfying conclusion and you get what you wish. Its jobs like this that put a bad name on us good tilers and its sad to hear. Good luck

Answered 24th Oct 2016

A.K.O Tiling Services

Member since 8 Jan 2016

No feedback

Hi, if it is a supspended floor wooden or chipboard or similar it should have been overboarded then tiled with a flexible adhesive and a flexible grout.
Firstly check whether this is the case.
if the adhesive is stuck to the floor and not the tiles then they have probably not put a scraping of adhesive on the back of the tiles as well as the floor, which generally should be the case with porcelain tiles.
From what you have said it does not appear that the tiles have been fixed or grouted properly, the fact they have moved argues the case perfectly the fitters have no argument, they should fix the loose tiles and re-grout as a minimum if they have not been fitted correctly I think you could rightly argue for them to be taken up and done again.

If they are decent tradesmen their reputation would lead them to doing it properly for you now if not the first time.
good luck

Answered 16th Jul 2014

Steve Gray Tiling Services

Member since 20 May 2013

Hello, this is quite common problem with tiles that are laid on plywood or wood subfloor. However it really should not happen at all when everything is done properly with use of right materials, so after just one year you should have right for full repair from the fitters, without aditional charge.

Answered 1st Sep 2014

Tile & Stone

Member since 29 Aug 2014

I'm really surprised anyone lay tiles on top of a wood. Its quite simple, wood sucks out the moisture out of the adhesive which not allows the glue to bond with both - tiles and wood which cause lack of stretch of the adhesive. Also when wood getting wet its start to expand, slightly but enough for tiles to come off.
Ply on the joists, then a cement board, hydro isolation which im getting from europe and then you ready to lay the tiles.
Hydroisolation is a material which not allowes any moisture to past its barrier, its a must for bathrooms with poor ventilation system. Its like PVA but much much stronger.
In areas of high moisture the tiles need to be layd in a very specific way with a small movement to eliminate air gaps and spread the adhesive evenly across the tile like the floor also. This way no moisture will go under the tiles and customer gives you a positive feedback on mybuilder.com :o)

Answered 12th Mar 2016


Member since 4 Mar 2016

Looks like a tile is lay down straight on plywood with is very flex material so is make ma move when You walk on he tiles will have to come up You have few ways to fix this :
1 . Fit pay wood least 18 mm ( quick and cheep way but not for long )
2 . Fit tile underlay mat ( good but expensive )
3. Fit tile board ( good but expensive )
4. fit a fabric mesh and put on top of this self level component ( best idea as mesh will never cam so easily like under lay mat surface ready to tiling will be hard like reinforced concrete )

Answered 14th Jan 2016

Peter Salek

Member since 29 Dec 2014

Wooden floors should always be ply'd over and fixed down with screws. After priming the floor the tiles should then be layed using flexible adhesive and then flexible grout ( can also use flexible additive ) .

Answered 7th Apr 2016

CS Ceramics

Member since 11 Mar 2016

6mm ply is way too thin, should be using a minimum of 15-18mm ply when tiling. I always use a cement backer board like hardiebacker which in this modern day should have been used. (No excuse from this tiler/bathroom fitter who did the job)

Answered 23rd Jun 2016

W.I.P Services

Member since 12 May 2016

If this is on to a timber floor the best product to have used is dittro matting this takes anymovemt out of the floor also a waterproofer aswell. Always use flexi adhesive n grout also remember to prime the floor as well and that the boards have been screwed every 4 inches

Answered 4th May 2017

Elite Tiling Services

Member since 14 Feb 2017

You should use some sort of matting like Ditra or Mapei do a version this is fixed to the floorboards using adhesive then you can lay tiles straight onto this, using a flexible adhesive and grout, but first make sure the floorboards are secure and sound, if not screw them down at regular intervals .

Answered 16th Jun 2017

Impressive Tiling

Member since 29 May 2017

Yes as mentioned, the floor must be repaid with sterling board to create a new flat base for the tiling to take place, also cement board is advised, and 100% need to use flexible adhesive and grout the no problems.

Answered 4th Oct 2017

Surrey Tiles

Member since 4 Oct 2017

No feedback

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